Debug stepping is not right for a loop with a single "print"

[dsyme]

We have a simple mistake in debug stepping for this simple loop, F11 doesn't step through the loop - it seems to be only when the loop body is a single statement/expression.

let h3 inp =
    for x in inp do
       printfn $"hello, x = {x}"

h3 [1..3]

As soon as you do anything else inside the stepping is fine:

let h3 inp =
    for x in inp do
       let y = 1
       printfn $"hello, x = {x}"

h3 [1..3]

[dsyme]

Labelling as a regression as this surely worked in the past. Impact high because it's about the simplest code possible.

[dsyme]

Fix of this and numerous other problems related to for-loop stepping is in #12432